1. What is the W-Index Formula?

The W-Index formula calculates rainfall depth based on the uniform infiltration rate after initial infiltration capacity has decreased, rainfall duration, and runoff depth. It provides an accurate assessment of precipitation in hydrological studies.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( W-\text{Index} \) — Uniform infiltration rate (m/s)
• \( \text{Rainfall Duration} \) — Length of rainfall event (s)
• \( \text{Runoff Depth} \) — Vertical height of water flow (mm)
• \( \text{Rainfall Depth} \) — Resulting precipitation depth (mm)

Explanation: The equation accounts for the relationship between infiltration rate, rainfall duration, and surface runoff to determine total precipitation depth.

3. Importance of Rainfall Depth Calculation

Details: Accurate rainfall depth estimation is crucial for hydrological modeling, flood prediction, water resource management, and irrigation planning in agricultural and environmental studies.

4. Using the Calculator

Tips: Enter W-Index in m/s, rainfall duration in seconds, and runoff depth in mm. All values must be valid non-negative numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is W-Index and how is it measured?
A: W-Index refers to the uniform rate of infiltration during a rainstorm after initial infiltration capacity has decreased, typically measured in cm/h or converted to m/s.

Q2: Why is rainfall duration important in this calculation?
A: Rainfall duration directly affects the total amount of water that infiltrates and runs off, making it a critical factor in determining total precipitation depth.

Q3: What are typical values for runoff depth?
A: Runoff depth varies based on soil type, land cover, and rainfall intensity, typically ranging from a few millimeters to several centimeters depending on conditions.

Q4: Are there limitations to this equation?
A: The formula assumes uniform infiltration rate and may be less accurate in extreme weather conditions, highly variable terrain, or areas with complex hydrological characteristics.

Q5: How can this calculation be applied in real-world scenarios?
A: This calculation is used in watershed management, flood control planning, irrigation system design, and environmental impact assessments where accurate precipitation data is essential.